WASHINGTON (WUSA9)--Sixteen year-old Leilani Tizon is a courageous teenager who talks candidly about an issue rarely discussed in public: suicide.

It's the 10th leading cause of death for Americans, and it leaves shattered families in its wake.

"It sounds harsh but I've spent the last five years thinking that my brother doesn't love me. And that this is my fault," Leilani told us, from the living room of her suburban Washington home.

Growing up, Leilani and Christopher Tizon were inseparable.

"My brother and I were best friends. We were 6 ½ years apart," she said. "He was 18 when everything happened. I was 11."

Their father, Robert, was on a deployment to Saudi Arabia with the Air Force, when Christopher put a loaded gun to his left temple and pulled the trigger.

"He was very handsome," said Leilani, glancing over her shoulder at a large framed photo of her brother. She smiles.

Leilani's father, Robert Tizon, struggles too. "I feel guilt," he said, "because as a parent, I wonder if I could have done better? What did I do wrong? Why didn't I recognize something?"

Added Leilani, "I don't want any kid to ever feel what I'm going through. I don't want any family to feel the grief and the misery that my family feels."

Leilani lives with enormous guilt for not telling her parents about Christopher's unusual behavior weeks before his death. The two were in his car when Chris appeared to have a breakdown after a long phone call with his Dad.

"You could tell my brother was furious. He was crying.And he was shaking. He was tearing leather off the steering wheel under his fingernails," she said. "He threw his cell phone in the back and started hitting himself with his fists, started banging his head against the steering wheel, against the window."

Normally a safe driver, she says Chris uncharacteristically sped off.

Recalled Leilani, "We were going about 85, 90, 95."

Her brother later apologized.

"I said just promise me nothing like that will ever happen again. He said, I promise. But you need to promise me that what happened today, you will never tell Mom and Dad," she said. "And him being my best friend, I kept that promise."

Leilani's voice wavers, "A month and a half later, I lost him."

"I miss his bear hugs," Robert remembered. "He would give me the biggest bear hugs and that's what I miss. His laughs, his bear hugs. Oh, to have those again!"

"I feel like if I did tell my parents the day after or as soon as possible, he would still be with us today," Leilani said.

Leilani has transformed her regrets into action. She now speaks to other teenagers and tells them suicide is never the answer.

"When you do feel down, simply take your right hand and place it over your heart and know that beating is called purpose. And that someone in this world needs you more than air," she said. "To know that you make someone out there smile every day or just seeing you around makes them smile, whether you know it or not, you do that to somebody and that's a reason to live,"

When Leilani speaks to other teenagers, she alerts them to some potential warning signs of suicide. They include: